Fingerprint identification uses unique fingerprint information of a human finger for identification. For a common fingerprint identification device, a complete fingerprint image is taken by a fingerprint sensor, and then is subjected to a fingerprint identification algorithm for fingerprint image processing and fingerprint minutiae extraction, so as to compare fingerprints. There are two common types of fingerprint identification devices, capacitive and optical. Optical fingerprint identification devices record fingerprints by means of a light source, a reflecting surface, and a photosensitive element. In use, a finger presses on the reflecting surface, crests and troughs of a fingerprint thereof reflect light, and an image is captured through the photosensitive element. Since crests and troughs of fingerprints are different in light reflecting intensity, a difference in scale is reflected after the photosensitive element senses the light intensity, thereby achieving the effect of fingerprint identification.
At present, optical fingerprint identification devices have a problem of insufficient light transmission due to the film layers and the structure blocking the light and the finger affecting the light reflectivity and absorptivity. Therefore, for the purpose of enabling the photosensitive element to sense sufficient light to stay capable of fingerprint identification, luminous intensity of the light source needs to be increased. However, the increase of the luminous intensity of the light source results in increased power losses and thus increased overall power consumption of the fingerprint identification device.